DEVELOPMENT OF A SEMI-INDUSTRIAL SCALE PROTOTYPE SYSTEM FOR THE PRODUCTION AND PURIFICATION OF ETHANOL FROM LOW-GRADE RAMBUTAN (NEPHELIUM LAPPACEUM) FOR GASOHOL APPLICATIONS

Abstract

This research explores ethanol production from low-quality rambutan as an alternative energy source. It aims to determine optimal fermentation conditions and study the distillation process for ethanol extraction during scale-up. The findings indicate that the ideal fermentation conditions involve preparing low-quality rambutan with 20 %w/v fruit pulp (weight per volume of rambutan juice), adding 0.96 g/L of Di-ammonium Phosphate; DAP as a nitrogen source, and sterilizing with 0.18 g/L Potassium Metabisulfite; KMS. Fermentation with selected S. cerevisiae TISTR 5339 yeast yielded a maximum ethanol concentration of 5.83 %v/v. Scaling up the fermentation to 18 liters in a 20-liter fermenter for 21 days increased ethanol production to 8.83 %v/v. Distillation using a fractional distillation system at 90 °C resulted in 50 %v/v ethanol concentration, which increased to 95 %v/v after four rounds of distillation. Further purification using zeolite molecular sieves (100 g) produced ethanol at 99.20 %v/v, suitable for blending with gasoline to create gasohol. The study demonstrates the feasibility of developing a semi-industrial ethanol production model, contributing to future renewable energy sources.